Method of making molybdenum and alloys of molybdenum



Patented Jan. 9, 1940 METHOD OF MAKING MOLYBDENUM AND 'ALLOYS OFMOLYBDENUM Joseph 11. Brennan, Niagara Falls, N. Y., assignor to ElectroMetallurgical Company, a corporation of West Virginia No Drawing.Application January 28, 1939, Serial No. 253,449

4 Claims. (01. 75-176) The principal ores of molybdenum, including thesulfide ore, molybdenite, very often contain substantial amounts ofcopper minerals, for

instance copper sulfide, which can not readily be separated from the oreby mechanical methods.

Inasmuch as there is a demand for metallic molybdenum andmolybdenumalloys containing one or more metals of the iron group (iron, cobalt,nickel) with little or no copper, a practical m method is needed forproducing these alloys from copper-contaminated molybdenite, roastedmolybdenite, or other molybdenum sources. It is an object of thisinvention to provide such a process. 5 In accordance with the invention,molybdenite,

roasted molybdenite, or other ore source of molybdenum, contaminatedwith copper mineral,

30 may be used. A moderate excess of reducing agent is desirable, but alarge excess should be avoided.

Soda ash is a satisfactory form of basis flux for use in this process.The sodium carbonate is 35 believed to enter into a chemical reaction ofthe type:

2NazCOs+MoS2+2C=2Na;S+2COz+2CO+Mo thereby supplying sodium sulfide tothe slag. A

40 substantial excess of sodium carbonate may be used. Lime, limestone,magnesia, or dolomite may be added to supplement the action of sodiumcarbonate by reactions of the type:

and to aid in fiuxing gangue materials, silicate for instance. Otherbasic, or neutral, fiuxing agents may be added if desired. Preferably, a

rather large excess of basic fluxes is added to 50 keep the slag basic.It is preferred, furthermore,

that sodium be the predominating base-forming element of the slag.

As indicated above, the sodium sulfide may be formed by reaction of sodaash with carbon and the sulfides in the ore. Altemately or additionally,sodium sulfide may be added to the slag; or sodium sulfate and areducing agent; or calcium sulfate, a reducing agent, and a sodiumcompound such as soda ash. The latter methods are particularly useful inthe treatment of oxidized ores of molybdenum.

The molybdenite material to be treated will ordinarily contain between25% and 60% molybdenum and 1% to 15% copper.

The following specific examples of processes embodying the principles ofthe invention serve to illustrate such principles, but it-will beunderstood that the scope of the invention is not limited to or by theseexamples.

Example I 100 parts of a molybdenite concentrate containing 34.2% M0,3.5% Fe, 1.5% Cu, 25% S, remainder chiefly gangue, was mixed with 100parts of soda ash, 50 parts of lime, 29 parts of iron (nail scrap), and27 parts of bituminous coal. The mixture was melted in an open-arcelectric furnace, the reactions completed, the slag removed, and thealloycast. The cast alloy contained 53.2% M0, 1.6% C, 0.13% Cu, 0.24% S,remainder iron. Thus, the ratio of Mo to Cu of about'22 in the ore wasraised to about 400 in the alloy. The slag contained 2.98% Mo and 0.45%Cu. 7

Example I! I ,3

100 parts of molybdenite concentrates containing 28.2% Mo, 10.9% Cu,10.9% Fe, 31.0% S, remainder chiefly gangue (ratio of Mo to Cu about2.6) was mixed with '72 parts of soda ash, 65

parts of lime, 10 parts of iron (nail scrap), and 25 parts of bituminouscoal. The mixture was melted and treated as in Example I. .The resultingalloy contained 69.6% Mo, 27.4% Fe, 1.4% Cu, 0.19% C, and less than0.08% S (a ratio of Mo to Cu of about49). The slag contained about 5%each of molybdenum and copper.

Example In 100 parts of the same concentrate as that used in Example 11was mixed with '75 parts of soda ash, 65 parts of lime, 13 parts of iron(nail scrap),

other than sodium carbonate may be used, and heating means other than anopen-arc electric furnace may be utilized. However, the preferredprocedure is that specifically described herein.

I claim:

1. Method of treating crude material containing reducible compounds ofmolybdenum and copper to produce a molybdenum alloy in which the ratioof molybdenum to copper is higher than in said crude material, whichincludes the step of reducing said compounds in the presence of a basicflux essentially containing sodium sulfide.

2. Method of making, from molybdenite material containing a substantialproportion of copper as copper sulfide, a molybdenum alloy in which theratio of molybdenum to copper is higher than in said molybdenitematerial, which comprises reducing said molybdenite material in thepresence of a basic slag essentially containing sodium sulfide.

3. Method of making, from molybdenite material containing a substantialproportion of copper sulfide, molybdenum alloys in which the ratio ofmolybdenum to copper is higher than in said molybdenite material, whichcomprises heating at a reaction temperature a mixture including saidmolybdenite material, coal, soda ash, and lime, and coalescing theresulting metallic molybdenum with molten metal of the iron group.

4. Method which comprises melting in an electric furnace a mixtureconsisting of the following ingredients in approximately the proportionsindicated: molybdenite containing 25% to 60% molybdenum and about 1% tocopper, 100 parts; bituminous coal, to parts; soda ash, 70 to 100 parts;lime, to parts; iron, 10 to 30 parts; and separating theresultinglow-copper alloy and high-copper slag.

JOSEPH H. BRENNAN.

